Radiopharmaceuticals are widely employed in nuclear medicine for imaging and for assessing physiological function and disease. Radioisotope renography is a form of kidney imaging involving radioisotopes used to image the kidney, evaluate suspected renal disease, and monitor renal function. The most common radiolabelled pharmaceutical agent used is Tc99m-MAG3 (mercaptoacetyltriglycine). Image quality is dependent on rapid removal of the radiotracer from the circulating plasma by the kidney as the rate of removal provides an important measurement of renal function. Renal plasma flow can be measured indirectly with radioiodinated o-iodohippuran (131I-OIH) that is generally accepted as a benchmark.
The 99mTc-MAG3 tracer is eliminated via the hepatobiliary tract which is exacerbated in patients with impaired renal function. The clearance of 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) is 50-65% when compared to 131I-OIH making the tracer suboptimal for the estimation of renal plasma flow. Thus, improved renal tracers are need.
Klenc et al. report fac-[ReI(CO)3(NTA)]2− and fac-[ReI(CO)3(L)]n− analogues as useful for assessing the renal clearance. Inorg. Chem., 2015, 54 (13), pp 6281-6290. See also Klenc et al. JNM 2015, 56, (Suppl. 3):654; Lipowska et al. J Nucl Med. 2014; 55 (Suppl. 1):1206, and U.S. Pat. Nos. 9,061,077 and 6,926,883.
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